rolff



No. 620,364. Patented Feb. 28, |899. L. w. G. ROLFF.

SAFETY ,DEVICE FDR ELEVATOl'iS.4

(Application tiled Feb. 21, 1898.) (N0 Modem 2 sheets-,sheet l.

' E ,g l u l l m @vih/mosca 5mm/144201,

No. 620,364. Pat'ented Feb. 28. |899. L. W G. RDLFF.

. SAFETY DEVICE FOB ELEVATDBS.

(Application led Feb. 21, 1898.)

(No Model.) 2 Sheets-Sheet 2- ll l lI JL @mum/tto@ i Mw@ j MM vUNrTEiDSTATES PATENT Ormes.

LOUIS W. G. vROLFF, OF NEW YORK, N. Y., ASSIGNOR OF ONE-HALF TO AUGUSTREHBOCK, OF SAME PLACE.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent N o. 620,364, datedFebruary 28, 189g. Application filed February 21,1898. Serial No.671,131. (No model.)

To @ZZ whom it may concern:

Be it known that I, LoUIs W. G. RoLFF, of the city, county, and State ofNew York, have invented certain new and useful Improvements in SafetyDevices for Elevators, of which the following is a full, clear, andexact specification, reference being had to the accompanying drawings,wherein Figure l is an elevation showing my safety device applied to anelevator, and Fig. 2 is an elevation showing my safety device in actionstopping the car. Fig. 3 is a sectional View on line 5 5, indicated inFig. l. Fig. 4 is an elevation, reverse view of Fig. 2. Fig. 5 is a topview of the safety device in action. Fig. 6 is a front view of one ofthe guides of the elevator.

Similar letters of reference indicate corresponding parts in all viewsof the drawings.

My invention relates to elevators; and it consists of an improvedautomatically-actin g safety device whereby the car when falling ordescending with a greater than a predetermined speed is securelystopped.

My safety device is illustrated in the drawings, wherein O representsthe upper beam or tie of the elevator F, and D the guide-rails of theelevator-shaft. Oar F is suspended by link a from cross-bar E, to whichthe hoisting-ropes h are suitably secured. i

The safety device consists of two independently-acting sets of catchesB, each set being connected by links ZJ to one block A, which areconnected each independently of the other by links c to cross-bar E.Adjustable springs g, having their upper ends fixed by pins g to theblocks A and their other ends secured to the beam C, draw the blocks Atoward the cross-beams. Top girder q is provided with slot q', whereinbolt o shifts, and in the position shown in Fig. l rests against theupper terminus of the slot. The length of the slot q is governed by therequired length of the motion of the blocks A, which are drawn up andcatches B receded by the action of the hoisting apparatus when liftingthe car. When the hoisting apparatus ceases to act, springs g draw theblocks toward beams O, and thereby project the catches B. Suchinstantaneous action upon the blocks A as is produced by the springs gis very material though not prerequisite or indispensable to theoperation of my safety device. The elasticity and the tension of thesprings g may be tested at any time by a pull on handles r, and maybeadjusted by setting accordingly the nuts ggon the screw-threaded ends ofthe springs.

Between the rear ends of catches B and the I lower inclined faces of.the sockets s springs 6o lare provided. Their upper ends are secured tothe blocks A and their lower slotted faces slide on screws o, set in thetermini of sockets s. These springs have a twofold purposefirst, to actas a buffer between the catches B and block A and also as an elasticsupport for the catches, while they operate as brakes in the mannershown in Fig. 2, and, second, to throw the catches B into recess m whentheir outer ends h slide off of the blocks Z. The springs thussupplement the coaction of the blocks A and catches B and also of thesprings g in driving catches B outwardly. Stoppingblocks Z are arrangedin alternating rows on both sides of the guidesD, as shown in Fig. 6 infront view.

By arranging blocks Z and recesses min alternating rows and by providingtwo independently-acting sets of blocks A and catches B the force of thejerk in stopping the car is greatly reduced, because immediately whenthe pull of the hoisting apparatus on the car is released one, oftenboth, pair of the catches B strike against the blocks Zand act asbrakes, slackening the speed of the car. The second advantage of thisarrangement is that even if the shock should be so great as to break thecatches striking rst the other pair will act immediately and safely stopthe car under any possible circumstances. In some instances only one setwill act; but mostly both sets will act at the same time, and in thiscase while the catches of one set act as a brake, retarding the motionof the car, the catches of the other set enter into the recesses m andstop it absolutely. When the ends of catches B have entered recesses mand support the stopped car, the strain is set upon the blocks A. Theview illustrated in Fig. 4 shows that the weight of the car rests uponthe ends of zoe the catches B, between beams Le and blocks u', whichsupport these ends, and thereby transfer the strain upon the structureof the car.

My safety device will act instantaneously under all conditions. If, forinstance, in the arrangement shown in sectional view, Fig. 3, one of thehoisting-ropes n should slacken, slip, or break while the other remainsintact, the cross-bar E would be disturbed in its horizontal (balanced)position, and as the pull upon the block A of the set nearest to thebroken or slackened rope would cease the block would then be movedinstantaneously downward by the sprin g g,and thereby catches B be setin action. In this case the descent of the car would be checked andstopped, though the other set of the apparatus might not at all be putin operation.

The operative capacity and readiness of the apparatus can be tested bystopping the car on the bottom of the shaft and letting one or bothhoisting-ropes n slacken or by stopping the hoisting machinery and thenlifting the car a few inches from below. When the apparatus is in actingorder, the car will stick in the position to which it Willbe lifted. Thecar will be movable upwardly, but will not descend.

I claim as my invention and desire to secure by Letters Patent- A safetydevice for elevators comprising two blocks, links connecting each of theblocks separately to the hoisting apparatus operating the car, andsprings connecting them to the body of the car, catches having theirrear ends connected to the blocks, a sliding connection between theelevatorcarand the hoisting apparatus, and two sets of stop-blocks,fixed in alternating rows, one row on each side of the guiding-rails ofthe elevator.

In witness that I claim the improvements described in the foregoingspecification I have signed my name in the presence of two subscribingwitnesses.

LOUIS W. G. ROLFF.

Vitnesses:

AUGUST REHBooK, RoBER'r VALENTINE MATHEws.

